Gallium Arsenide Safety.

[ImanCarrot]

Anyone machined this stuff? I have an enquiry from a customer but I hear the stuff, although not intrinsicaly toxic, can libreate Arenic and Gallium compounds which, when in contact with water, acids or alkalais can give off nasty stuff.

If I was to ingest some Gallium Arsendie dust while turning it, would the moisture in my lungs and/ or acid in my stomach constitute a risk?

I have searched all day for info on this stuff and although it says there's nothing on GaAs being toxic, I have found comprehensive (and sometimes contradictory) information on Arsenic and Gallium compounds being bad.

There's no data on the LD50 or LC50 values for GaAs.. anyone know where I can find it? (LD50 and LC50 are measures of how much material is required to kill 50% of the animals it's being tested on via various routes- see http://orgchem.colorado.edu/safety/tox.html for more info).

Many thanks in advance.

Iain.

[messar]

Here is a link to an MSDS. (google GaAs MSDS)

http://www.wafertech.co.uk/msds/msds_gaas.html

Also, http://en.wikipedia.org/wiki/GaAs

I wouldn't worry about handling of bulk material, but turning, or grinding would need ventilation and fume extraction. Also, the waste needs to be treated as toxic material. (coolant, etc)

I believe that it also dissociates into Gallium and Arsenic if burned.

On a more practical level, it's also very brittle.

I work with GaAs wafers, but I'm not a safety guy, so I'm sure there's a lot more you need to know.

Matt

[ImanCarrot]

Thanks Matt,

Reading between the lines on all the safety details, it seems like this stuff is too toxic to machine. I've looked at various data over the past couple of days on this stuff and they all seem to say the crystal is safe as GaAs, but can liberate As and Ga compounds in contact with acids etc.

To my thinking then, if you swallow some of the dust it will be in contact with acid in you stomach and this would give off arsenic inside you... I'm gonna "no bid" on this one and offer him Germanium instead.

Thanks for your input mate.

Iain.

[Xerxes]

GaAs could be quite dangerous stuff. I work in university department where they make laser diodes from GaAs wafers and they take every precaution to avoid direct contact to bulk material or GaAs dust.

For few researchers measured arsenic content in blood has been too high even when they don't do mechanical machining of the stuff. They just split wafers to separate discrete laser chips from it which may release some dust particles from it.

[harryn]

For those that might read this down the road, GaAs dust is quite dangerous, at least long term exposure. I am pretty sure that it is a carcinogen. Short term exposure, I am not so sure.

[safeT]

I once had to fix a machine that machined or worked on GaAs, silicon, and Indium Phosphine wafers.

About this time I got really sick somehow.

I was never given proper gear to separate myself from the dust which can stick to your hands underneath your fingernails. Go eat lunch and you might get what PPM or PPT and the effect ?

Do not work with this stuff and don't work at University of Houston.

Check NIH.gov for known carcinogens such as Gallium Arsenide and see the results.

Do not work with any dust from any semiconductor period.